This invention relates generally to component enclosures and, more particularly, to systems and methods for enhancing natural convection cooling of component enclosures.
In at least some known application areas, it is important for components and systems to be light weight and reliable, for example, systems, including the various digital and power electronics systems that provide computational power and electrical power to an aircraft. Passive cooling of components is known to be reliable. However, passive cooling is also the least effective cooling method from a cooling performance point of view, typically resulting in a larger system for a given amount of cooling. Some options that are used to extend the capability of passive cooling include extended surfaces and new material with higher thermal conductivity. Extended surfaces increase the heat transfer area. Extended surfaces include fins, ribs, and other protrusions. Materials with higher thermal conductivity decrease the thermal resistance of the enclosure. Both extended surfaces and new higher thermal conductivity material achieve higher performance without affecting the simplicity and reliability of natural convection. However, they have performance limitations.
When the loss density extends that where passive cooling is practical, then active gas or liquid cooling is employed. Active gas or liquid cooling may result in a lighter, but less reliable system. When improvements made using extended surfaces and advanced materials reach their limit, active cooling, using a fan or other gas cooling device, can be used wherein a cooling gas is forced across and/or against the surface, reducing the fluid film thermal resistance substantially compared to natural convection. In addition to taking cooling air available from the immediate vicinity, the cooling gas in a forced convection approach could be conditioned, making it colder, and thus more effective. A further option is liquid cooling. Liquids, typically are a more effective heat transfer fluid than gas, and thus can remove more heat. Active gas cooling and liquid cooling are less reliable and more complex than a passive cooling system and they both require systems with moving parts which are inherently less reliable than a passive cooling approach.